Let-offs for use on looms



July 24, 1956 J. o. HUNT 2,755,824

LET-OFFS FOR use on LOOMS Filed Oct. 8, 1953 5 Sheets-Sheet 1 2/ INVENTOR. F/G/ John 0. Hur if A f fomeys Jul 24, 1955 J. o. HUNT 2,755,824

LET-OFFS FOR USE ON LOOMS Filed Oct. 8, 1953 5 Sheets-Sheet 2 INVENTOR. John 0. H 00/ @MZMMM Afforneys.

July 24, 1956 Filed Oct. 8. 1953 J. O. HUNT LET-OFFS FOR USE ON LOOMS 5 Sheets-Sheet 5 INVENTOR.

J0/7/7 0. Hum

y 1956 J. o. HUNT 2,755,824

LET-OFFS FOR USE ON LOOMS Filed Oct. 8, 1953 s Sheets-Sheet 4 Ill Afforneys July 24, 1956 J. o. HUNT 2,755,824

LET-OFFS FOR USE ON LOOMS Filed Oct. 8, 1953 5 Sheets-Sheet 5 INVENTOR.

John 0 Hum Al/ameys LET-UFFS FOR USE (IN LGOM John 0. Hunt, Greenviile, S. C.

Application October 8, 1353, Serial No. 384,389

Claims. (Cl. 13110) This invention relates to let-off mechanisms used in looms to let oif the warp yarns from the beam at a rate varying with variations in the tensions on the yarns. More particularly, the invention is concerned with a novel let-off so constructed that it maintains the warp yarns under the desired tension at all times and, particularly at the time of the beat-up, but quickly releases the tension on the yarns in the event of the abrupt stoppage of the loom referred to as bang-off and resulting from the shuttle not completing its flight and being trapped in the shed.

Let-offs now in common use on looms control the rate, at which the warp beam rotates, and thereby maintain the desired tension on the warp yarns. In let-offs of one type, the beam is rotated by the pull of the yarns, as the cloth is taken up, and the let-off includes a friction brake retarding the rotation of the beam and made effective by means of weights. Positive let-offs incrude a let-off shaft, which is connected to the warp beam and is driven at a rate varying with variations in the warp tension. Let-ofis of bath types are subject to the disadvantage that they do not permit the whip roll to move and release the tension on the warp yarns sufficiently quickly and to the required extent to protect the warp yarns against damage in the event that the shuttle stops within the shed and is forced by the lay toward the fell of the goods.

The let-oif of the invention overcomes the disadvantages of the prior let-oifs, in that the whip roll can move quickly to release the tension on the warp yarns upon the occurrence of a bang-off. At all other times, the Whip roll resists movement by the warp yarns in order to subject them to the desired tension and, at the time of the beat-up, is held fixedly in place and cannot be moved by the warp yarns.

In the new let-off, the support for the whip roll is movable and it is urged in one direction by the tension of the yarns acting on the roll. The support is urged in the opposite direction by yielding means, which preferably apply a constant pressure to the support regardless of its position within its range of movement. The means, by which rotation of the beam to let off yarn therefrom is effected, is controllable to vary the rate of let-off, and such control is exercised through a connection to the whip roll support. The construction is such that, as the support moves in response to an increase in the tension on the yarns, the rate of let-off is increased, and vice versa. The connections between the support and the means effecting rotation of the beam are such as to permit a rapid movement of the support to release the tension on the yarns when the tension increases sharply as an incident to a bang-off. Under normal conditions, the support moves in accordance with variations in the tension on the yarns, but means operating in timed relation to the lay holds the support stationary at the time of the beat-up.

The preferred form of the new let-off is of the positive type and it includes a variable speed device having an input shaft connected to a Ioom shaft operating continuously during the operation of the loom, and an outnited States atent A put shaft, which is connected to a let-off shaft in turn connected to the beam. The variable speed device may take different forms, but preferably includes a constant speed disc assembly connected to the loom shaft and one or more variable speed disc assemblies driven by the constant speed disc assembly.

For a better understanding of the invention, reference may be made to the accompanying drawings, in which Fig. 1 is a view in side elevation of one form of the new let-off with parts broken away;

Fig. 2 is a partial plan view of the let-off shown in Fig. 1;

Fig. 3 is a view similar to Fig. 1 but showing the parts in different positions;

Fig. 4 is a view in side elevation, with parts broken away, of a modified form of the new let-off;

Fig. 5 is a View in side elevation, with parts broken away, of a second form of the new let-off;

Fig. 6 is a view of the let-off of Fig. 5 in end elevation; and

Fig. 7 is a sectional view on the line 77 of Fig. 5.

In Fig. 1 of the drawings, one form of the new let-off is illustrated as being installed on a loom having sides 10, of which only one is shown. The side has a bracket 11 providing a bearing for the journal 12 of a loom beam 13 and the other journal of the beam is mounted in a bearing in a corresponding bracket on the other loom side. The beam is of the usual type having. heads provided with gears and the gear on the beam head shown in Fig. 1 is indicatediat14.

Each of the sides 10 is provided with a bracket 15 having a bearing for one end of a shaft 16 and the shaft has arms 17 carrying bearings for shafts 18. Each shaft 18 carries an arm 19 receiving one end of the shaft 20 of a whip roll 21. One. of the shafts 18 is provided with an arm 22 carrying a roller 23 engaging a cam 24 on the crank shaft 25 of the loom and the cam 24 is so mounted on the crank shaft arm that, at the time of the beat-up, the roller 23 is in its uppermost position and the whip roll 21 is likewise at its highest point with reference to arms 17.

The loom side 10 is provided with a pair of brackets 26, 27, in which is mounted. a stationary shaft 28, and the shaft is enclosed within three separate lengths of tubing. The tube 29 adjacent the bracket 26 has a worm wheel 30 fast' thereon and driven by a worm: 31 On a shaft 32 in bearings attached to the loom side. Shaft 32 is provided with a gear driven through gear 33 by a gear 34- on the loom cam shaft 35. Adjacent the worm gear 30, the tube 29 carries a driving disc assembly comprising a coned disc 36 rigidly connected to tube 29 and a similar disc 37, which is splined to the tube to rotate therewith but is movable axially thereof. Disc 36 has an integral hub entering a housing 38, which is hollow and receives one end' of the outer member of a ball thrust bearing 39, the inner member of which receives one end of tube 29.

The central section 40 of the tubing has one end received within; the inner member of the bearing 39. The end of .the bearing outside housing 38 enters a cavity in a hollow housing 41 enclosing the hub of a coned-disc 42 splined to tube 40. Disc 42' faces a similar coned disc 43 fast on the tube.

The third section 44 of the tubing encloses the portion of the shaft 28 adjacent bracket 27 and it is connectable to tube 40 bya clutch indicated diagrammatically at 44a. The tube 44 also carries a worm 45 driving a worm wheel 46 fast on the let-off shaft 47, which is provided with a pinion 48 meshing with the gear 14 on the adjacent end of beam 13. Tube 44is also provided witha hand Wheel 49, which hand wheel can be operated, whenthe: clutch is disengaged, to rotate worm 45, etc, to turn beam 13 to take up slack in the warp yarns.

Above the shaft 28, the loom side is provided with brackets 58a, 5% having hearings, in which a shaft 51 is mounted for rotation. Adjacent bracket 50a, a coned disc 52 is mounted on the shaft and splined thereto, so as to rotate with the shaft but to be movable axially thereof. Facing disc 52 is a similar disc 53 rigidly secured to the shaft. A similar disc assembly including a disc 54 splined to the shaft and a disc 55 fast on the shaft is mounted on the shaft adjacent bearing 50b. A belt 56 connects discs 36, 37 on tube 29 to discs 52, 53 on shaft 51 and a belt 57 connects discs 54, 55 on the shaft to discs 42, 43 on tube 40.

With the arrangement described, the rotation of the cam shaft causes a rotation of tube 29 and of discs 36, 37 at a fixed rate. The discs drive discs 52, 53 through belt 56 at a rate determined by the separation of the discs of the two pairs. The rotation of discs 52, 53 drives shaft 51 and discs 54, 55 and the latter discs drive discs 42, 43 and tube through belt 57. The rotation of tube 40 causes tube 44 and worm to rotate to drive the let-01f shaft 47. The rate, at which the let-off shaft is driven, depends on the separation of the discs of the several disc assemblies.

The loom side 10 is provided with one or more brackets 58, in which a rod 59 is supported for endwise movement adjacent shaft 51. The rod is provided with an arm 60 carrying a housing 61 having an opening, through which shaft 51 extends and in which is mounted a thrust hearing diagrammatically shown at 62. One member of the thrust bearing engages housing 61 and the other acts on disc 52. Adjacent disc 54, the rod 59 is provided with a second arm 63 carrying at its lower end a housing 64, through which shaft 51 extends and in which is mounted bearing 65 similar to hearing 62 and having one member .engaging the housing 64 and the other the adjacent disc 54. A spring 66 encircling the rod 59 acts on arm 60 and bracket 58 and urges the rod endwise to permit an increase in the separation between discs 52, 53. When the rod is so moved, the arm 63 causes a corresponding decrease in the separation of discs 54, 55. When discs 52, 53 approach each other, the belt 56 moves toward the peripheries of the discs and moves a corresponding distance inward between discs 36, 37, so that discs 36, 37 drive discs 52, 53 at a reduced speed. Similarly, as the separation between discs 54, 55 increases coincidentally with a decrease in the separation of discs 52, 53, belt 57 moves inward between discs 54, 55 and correspondingly outward between discs 42, 43. Separation of discs 54, 55 thus corresponds to a reduction in the rate, at which these discs drive discs 42, 43. Accordingly, spring 66 is constantly urging rod 59 to a position producing an adjustment of the disc assembly resulting in a reduction of the speed, at which the let-off shaft 47 is driven and the yarn leaves beam 13.

The rod 59 carries a slotted link 66, which is connected by a pin 67 within the slot to an arm 68 fast on shaft 16 carrying the arms 17 supporting the whip roll. The arm 68 is also connected by a pin 69 to a rod 70 connected to a piston within a cylinder 71 having an inlet behind the piston, to which air under pressure is supplied through a line 72 from a source (not shown), such as a tank of substantial size kept filled by a motor-driven pump. The air acting on the piston within cylinder 71 continually urges the piston outwardly and thus acts on arm 68 and urges shaft 16 in a clockwise direction. Such angular movement of shaft 16 tends to raise the Whip roll 21 and increase the tension on the warp yarns.

A ratchet bar 73 is mounted on an arm 68 and its teeth lie along an arc at the lower end of the bar. The teeth are engageable by a plurality of pawls 74 pivotally mounted at 75 on bracket 15 and secured by bolts 76 to an arm 77 pivotally attached to arm 22. Springs 78 encircling the bolts urge the pawls 74 upward toward the lower end of arm 77.

In the operation of the let-off described, the cam 24 is mounted on the crank shaft 25 in such position that the lobe of the cam is in substantially vertical position, as shown in Fig. 1, at the time the lay is beating up an inserted pick and arm 22 is in its highest position. The shafts 18 have, accordingly, been rocked counter-clockwise to swing arms 19 and raise the whip roll 21 to apply tension to the warp yarns W. As the arm 22 is moved to its uppermost position, it acts through arm 77 to raise the pawls 7 4 and, when these pawls engage the teeth on ratchet bar 73, the arm 68 is prevented from swinging counterclockwise. The whip roll support, comprising shaft 16 and arms 17, is thus held by the ratchet bar and pawls against movement by the warp yarns at the time of the beat-up.

If the shuttle is trapped in the shed, the movement of the lay toward the fell of the fabric to effect the beat-up will cause the reed to engage the shuttle and move it toward the fell. The absence of the shuttle from the box will then cause the appropriate stop motion to stop the loom. However, before the loom stops, the engagement of the reed with the shuttle will greatly increase the tension on the warp threads and it is desirable that, under the conditions described, the tension be released quickly, so that no threads will be broken. This action is effected with the new let-off, as illustrated in Fig. 3.

The let-01f is shown in Fig. 3 with the parts in the same position as shown in Fig. 1, except that cam 24 is in the position, at which the loom bangs off when the shuttie is trapped in the shed. Prior to the stopping of the loom, the increased tension on the warp threads has caused a downward movement of the whip roll with an accompanying counter-clockwise movement of arms 17, shaft 16, and arm 68. The arm 68 may be moved, as described, independently of the corresponding adjustment of the variable speed device, because of the slot and pin 2 connection between the arm and link 66 At the time the movement of the arm occurs, the pawls 74 are in their down position and thus free of ratchet bar 73, because the lobe of cam 24 is approximately horizontal instead of being upright, as shown in Fig. l.

The variable speed device shown in Fig. l, which includes two sets of disc assemblies, permits variation in the ratio of speeds of the input and output shafts of the device through a wide range. A loom equipped with such a device can, accordingly, be used without change in worm 45, worm gear 46, or pinion 43, not only throughout the consumption of all the warp yarn on the beam, but also in the production of fabrics having a considerable variation in the number of picks per inch. Where the loom is not intended to be used in the production of fabrics of varying constructions, the let-oils shown in Figs. 4 and 5 may be preferred to those shown in Fig. 1.

In Figs. 4 and 5, the parts of the loom and the let-off, which are the same as those shown in Fig. 1, are identified by the same reference characters as in Fig. l.

The let-off shown in Fig. 4 is mounted on the loom side 10 having a bracket 11 supporting one journal 12 of the beam 13 having gear 14 on its heads. A bracket 15 attached to the side supports a shaft 16 carrying arms 17 adjacent the two sides of the loom. Each arm 17 supports a shaft 18 provided with an arm 19 supporting one end of the shaft 20 of the whip roll 21. An arm 22 fast on one shaft 18 carries a cam follower roller 23 engaging a cam 24 on the crank shaft 25 of the loom.

A shaft 79 is mounted in bearings in brackets 80, 81 attached to the loom side and the shaft carries a worm gear 82 driven by a worm 83 on the cam shaft 35 of the loom. A constant speed disc assembly is mounted on shaft 79 and comprises a coned disc 88 fast on the shaft and a similar disc 89 splined to the shaft, so that it cannot move angularly relative to the shaft but is freely movable axially. To effect such axial movement of disc 89, a sleeve 90 is mounted to encircle the shaft and an anti-friction bearing, shown diagrammatically at 91, is

mounted to surround the shaft and to lie between one end of sleeve 90 and the adjacent end of the hub 89a of disc 89. A spring 92 encircling the shaft bears against bracket 81 and sleeve 90 and tends to urge sleeve 90 to force disc 89 toward disc 88.

A second shaft 93 is mounted in hearings in brackets 94, 95 attached to the loom side and the shaft carries a disc assembly, of which disc 96 is fast on the shaft and disc 97 is splined to the shaft. Disc 97 is urged toward disc 96 by a spring 98 interposed between disc 97 and a collar 99 on the shaft. The disc assemblies 88, 89 and 96, 97 are connected by a belt 100.

A second shaft 101 is mounted in brackets 102, 103 on the loom side 10 in axial alignment with shaft 93 and the shafts can be connected by a clutch 104 having a member attached to each shaft. A worm 45 is mounted on shaft 101 and meshes with a worm gear 46 on the let-off shaft 47, which also carries a gear 48 meshing with the gear 14 on the head of the beam. Shaft 101 also carries a hand wheel 49, by which the shaft can be rorated to take up the slack in the warp yarns, when clutch 18-4 is disengaged, as shown.

The sleeve 90, by which disc 89 is moved relative to disc 88, is connected by a link 105 to an arm 68 rigidly attached to shaft 16. Link 105 has a slot 105a receiving a pin 67 on arm 68 and the arm carries a second pin 69, to which is connected a rod 70 attached to a piston within a cylinder 71. The cylinder is supplied with air under pressure through a line 72 and the air tends to force rod '78 to swing arm 68 clockwise.

Arm 68 is provided with a ratchet bar 73 engageable by pawls 74 pivoted at 75 on bracket 15. The pawls are suspended on bolts 76 attached to an arm 77 depending from the arm 22. The bolts are surrounded by individual springs 78, which tend to hold the pawl 74 against the end of arm 77.

With the construction illustrated in Fig. 4, the beam 13 is rotated by the let-off shaft at a rate depending on the adjustment of the variable speed device including the disc assemblies 88, 89 and 96, 97. Spring 92 tends to move disc 89 of the driver assembly toward disc 88, so that belt 100 engages discs 88, 89 near their peripheries. Under such conditions, the variable speed device drives the let-01f shaft at the maximum rate. The action of spring 92 tends to swing arm 68 counter-clockwise and the arm spring is urged in the opposite direction by the air pressure within cylinder 71. When the arm moves clockwise, it permits discs 88, 89 to separate farther, so that belt 188 will move toward the common axis of the discs and thus rotate the output shaft 93 at a lower speed.

When the whip roll 21 is moved down under the tension of the warp yarns, arm 68 is moved counter-clockwise against the resistance of the air pressure Within cylinder 71 and spring 92 then acts to cause disc 89 to approach disc 88. When the excessive tension on the warp yarns is removed, the air pressure within cylinder 71 swings arm 68 clockwise and sleeve 90 is moved away from the discs 88, 89, so that the discs may separate and the variable speed device may rotate shaft 93 at a lower speed.

The ratchet bar 73 and pawls 74 are operative, as pre viously explained, to hold arm 68 against movement at the time of the beat-up and thus prevent movement of the whip roll 21 by the yarns. If the shuttle is trapped in a shed and excessive tension is applied to the warp yarns, this tension will develop at a time before the pawls 74 are engaged with the ratchet bar. Accordingly, when such tension is applied to the whip roll, arm 68' will quickly swing clockwise and thereby release the tension on the yarns and prevent their breakage. The use of the slot and pin connection between arm 68 and link 105 permits the rapid counter-clockwise movement of arm 68 before the completion of the accompanying adjustment of the variable speed device. If arm 68 had merely a pivotal connection to link 105, the arm could not move except with the discs, .and the release of tension on the warp yarns would be correspondingly slow.

In the form of the device shown in Figs. 5 to 7, incl., a shaft 106 is mounted in hearings in brackets 107, 108 attached to the loom side 10 and carries a worm gear 109 driven by a worm 110 on a shaft 111, which is driven through a chain or belt 112 from the crank shaft 113 of the loom. A driving disc assembly is mounted on shaft 106 and includes a coned disc 114 fast on the shaft and a similar disc 115 splined on the shaft for rotation there with and free movement axially of the shaft. A disc 115 has a hub lying within the inner member of a ball thrust bearing 116. The outer member of the bearing lies within a cup 117 encircling shaft 116 and provided with a pair of axial projections 118, 119. A vertical shaft 120 is mounted in bearings 121, 122 attached to the loom side 10 and the shaft has a pair of curved arms 123, 124 fast thereon. The arms extend to opposite sides of shaft 106 and lie against the outer face of cup 117 adjacent the projections 118, 119. A torsion spring 125 encircling shaft 120 has one end attached to the shaft and the other end attached to bracket 122. The spring acts to rock shaft 120 to cause the ends of arms 123, 124 to bear against the end of cup 117.

Shaft 120 carries a collar 126 having an arm 127 engageable with the hooked end of a rod 128 carrying a link 66 having a slot receiving a pin 67 on a lever 68. The lever 68 is part of the whip roll support of the kind illustrated in Figs. 1 and 3 and is swung counter-clockwise as the tension of the warp yarns on the whip roll increases. Lever 68 has a pin 69, to which is connected a rod 70 connected to apiston within a cylinder 71 containing air under pressure supplied through a line 72. Rod 68 carries a ratchet bar 73 engageable by pawls 74 pivoted at 75 on the bracket 15. The pawls are secured by bolts 76 to a link 77 connected to an arm like arm 22 and the bolts are held in place on the link by springs 78.

Shaft 120 carries an arm 129 connected by a link 130 to an arm 131 on a shaft 132 mounted parallel to shaft 120 in bearings in brackets 133, 134 attached to the loom side. Shaft 132 carries a pair of arms 135, 136, which straddle a horizontal shaft 137 mounted in bearings in brackets 1'38, 139 attached to the loom side.

Shaft 137 carries a driven disc assembly, which comprises a coned disc 140 fast on the shaft and a similar disc 141 splined to the disc. Disc 141' has a hub lying Within the inner member of a ball thrust bearing 142 and the outer member of the thrust bearing lies within a cup 143. The outer face of the cup is provided with a pair of projections 144 and the ends of arms bear against the face of the cup and engage the projections. The driver disc assembly 114, 115 is connected to the driven disc assembly 140, 141 by a belt 145.

Shaft 137 carries a worm 146 fast thereon and engageable with the worm gear 46 on the let-off shaft 47. As in the prior constructions, the let-off shaft has a gear meshing with the gear on the adjacent head of a Warp beam mounted in the beam supports. Shaft 137 may be divided into two parts connected by a clutch, so that the part of the shaft directly connected to the let-off shaft through the worm and worm wheel can be rotated by a hand wheel 49 in order to take up the slack on the warp.

The modified form of the let-off illustrated in Figs. 5 to 7, incl., functions in a manner similar to the let-off shown in Fig; 4. The torsion spring 125 tends to move disc 115 toward disc 114 and thus increase the speed, at which the output shaft 137 rotates the let-off shaft, and the spring also acts to hold disc 141 in proper relation to disc 140. The air pressure within cylinder 71 tends to force arm 68 clockwise and the arm acts through link 66, etc., to hold shaft 120 against rotation by the torsion spring. Arm 68 can be swung clockwise by increased tension'on the warp yarns bearing against the whip roll,

but, at the time of the beat-up, the pawls 74 engage the teeth of ratchet bar 73 and the arm 68 is held against movement by the yarns. In the event that the shuttle is trapped in the shed, the increased tension on the Warp yarns causes arm 68 to counter-clockwise quickly to release the tension and this movement of the arm is possible, because, at the time the increased tension on the threads develops as the result of the shuttle being trapped, the pawls 74 are below and out of contact with the teeth on the ratchet bar 73. Also, the arm may be moved counter-clockwise independently of the variable speed device because of the slot and pin connection between the arm and link 66.

My copending application Ser. No. 357,744, filed May 27, 1953, discloses a let-off having features in common with that herein disclosed.

I claim:

1. A let-off for use in a loom having means for holding a warp beam and a lay for beating up inserted picks of filling, which comprises a whip roll engaged by the warp yarns being let off the beam, a support for the whip roll, the support being movable and urged in one direction by the tension of the yarns acting on the whip roll, means urging the support in the opposite direction, means for effecting rotation of the beam to let off yarn therefrom, means responsive to movements of the whip roll support resulting from variations in the tension on the yarns for controlling the rate of rotation of the beam, and means operating in timed relation to the lay for holding the whip roll support against movement by the yarns at the time of the beat-up, said support holding means including a ratchet bar secured to and movable with the support, and a pawl oscillated with the lay and engaging the ratchet bar at the time of the beat-up.

2. A let-off for use in a loom having means for holding a warp beam and a lay for beating up inserted picks of filling, which comprises a whip roll engaged by the warp yarns being let oif the beam, a pair of arms carrying the whip roll, a support, in which the arms are mounted for oscillation, the support being movable and urged in one direction by the tension of the yarns acting on the whip roll, means urging the support in the opposite direction, cam means for oscillating the whip roll arms in timed relation to the lay, means for eifecting rotation of the beam to let off yarn therefrom, means responsive to movements of the whip roll support resulting from variations in the tension on the yarns for controlling the rate of rotation of the beam, and means operating in timed relation to the lay for holding the whip roll support against movement by the yarns at the time of the beat-up.

3. A let-off for use in a loom having means for holding a warp beam and a lay for beating up inserted picks of filling, which comprises a Whip roll engaged by the warp yarns being let off the beam, a pair of arms carrying the whip roll, a support, in which the arms are mounted for oscillation, the support being movable and urged in one direction by the tension of the yarns acting on the whip roll, means urging the support in the opposite direction, cam means for oscillating the whip roll in timed relation to the lay, means for effecting rotation of the beam to let off yarn therefrom, means responsive to movements of the whip roll support resulting from variations in the tension of the yarns for controlling the rate of rotation of the beam, and means operated by the cam means in timed relation to the lay for holding the whip 'roll support against movement by the yarns at the time of the beat-up.

4. A let-off for use in a loom having means for bolding a warp beam and a lay for beating up inserted picks of filling, which comprises a whip roll engaged by the warp yarns being let off the beam, a support for the whip roll, the support being movable and urged in one direction by the tension of the yarns acting on the whip roll, means applying constant pressure to the support to urge it in the opposite direction, means for effecting rotation of the beam to let off yarn therefrom, means responsive to movements of the whip roll support resulting from varaiations in the tension on the yarns for controlling the rate of rotation of the beam, and means operating in timed relation to the lay for positively holding the whip roll support against movement by the yarns at the time of the beat-up.

5. A let-off for use in a loom having means for holding a warp beam and a lay for beating up inserted picks of filling, which comprises a whip roll engaged by the warp yarns being let oif the beam, a support for the whip roll, the support being movable and urged in one direction by the tension of the yarns acting on the whip roll, means urging the support in the opposite direction, a let-01f shaft adapted to be connected to the beam and rotatable to rotate the beam to let off Warp yarns, means for driving the shaft, means responsive to movements of the whip roll support resulting from variations in the tension on the yarns for positively controlling the driving means, and means operating in timed relation to the lay for holding the whip roll support against movement by the yarns at the time of the beat-up.

6. A let-off for use in a loom having means for holding a warp beam and a lay for beating up inserted picks of filling, which comprises a whip roll engaged by the warp yarns being let off the beam, a support for the whip roll, the support being movable and urged in one direction by the tension of the yarns acting on the whip roll, means urging the support in the opposite direction, a let-off shaft adapted to be connected to the beam and rotatable to rotate the beam to let oif warp yarns, a loom shaft operating continuously during the operation of the loom, a variable speed device having an input shaft connected to the loom shaft and an output shaft connected to the let-off shaft, means responsive to movements of the whip roll support resulting from variations in the tension on the yarns for controlling the driving means, and means operating in timed relation to the lay for positively holding the whip roll support against movement by the yarns at the time of the beat-up.

7. A let-off for use in a loom having means for holding a warp beam and a lay for beating up inserted picks of filling, which comprises a whip ro-ll engaged by the warp yarns being let oif the beam, a support for the whip roll, the support being movable and urged in one direction by the tension of the yarns acting on the whip roll, means urging the support in the opposite direction, a let-off shaft adapted to be connected to the beam and rotatable to rotate the beam to let oif warp yarns, a loom shaft operating continuously during the operation of the loom, a variable speed device having an input shaft connected to the loom shaft and an output shaft connected to the let-off shaft, the device being adjustable to vary the ratio of the speed of its shafts, means responsive to movements of the whip roll support resulting from variations in the tension on the yarns for adjusting the variable speed device, means biasing the variable speed device toward an adjustment, in which its output shaft has the highest speed, and means operating in timed relation to the lay for holding the whip roll support against movement by the yarns at the time of the beat-up.

8. A let-off for use in a loom having means for holding a warp beam and a lay for beating up inserted picks of filling, which comprises a whip roll engaged by the warp yarns being let off the beam, a support for the whip roll, the support being movable and urged in one direction by the tension of the yarns acting on the whip roll, means urging the support in the opposite direction, means for effecting rotation of the beam to let otf yarn therefrom, a variable speed device for controlling the rate of rotation of the beam, a connection between the whip roll support and said device, through which the support acts to vary the action of the device in response to movements of the support resulting from variations 9 in the tension on the yarns, and means operating in timed relation to the lay for positively holding the whip roll support against movement by the yarns at the time of the beat-up.

9. A let-off for use in a loom having means for holding a warp beam and a lay for beating up inserted picks of filling, which comprises a whip roll engaged by the warp yarns being let off the beam, a support for the whip roll, the support being movable and urged in one direction by the tension of the yarns acting on the whip roll, means urging the support in the opposite direction, means for effecting rotation of the beam to let off yarn therefrom, a variable speed device for controlling the rate of rotation of the beam, means urging the device to effect a faster rotation of the beam, a connection between the whip roll support and said device, the support acting through the connection to vary the action of the device in response to movements of the support resulting from variations in the tension on the yarns and the connection permitting the support to yield to an increase in tension, and means operating in timed relation to the lay for holding the whip roll against movement by the yarns at the time of the beat-up.

10. A let-off for use in a loom having means for holding a warp beam and a lay for beating up inserted picks of filling, which comprises a whip roll engaged by the warp yarns being let off the beam, a support for the whip roll, the support being movable and urged in one direction by the tension of the yarns acting on the whip roll, means urging the support in the opposite direction, means for rotating the beam to let off yarn therefrom, said rotating means including a first driving disc assembly, a first driven disc assembly, a second driving assembly, the first driven and second driving assemblies being driven in unison by the first driving assembly, and a second driven disc assembly driven by the second driving assembly and connected to the beam, and means responsive to movements of the whip roll support resulting from variations in the tensions on the yarns for adjusting the first driving and driven assemblies and the second driving and driven assemblies to vary the rate of rotation of the beam.

ll. A let-off for use in a loom having means for holding a warp beam and a lay for beating up inserted picks of filling, which comprises a whip roll engaged by the warp yarns being let off the beam, a support for the whip roll, the support being movable and urged in one direction by the tension of the yarns acting on the whip roll, means urging the support in the opposite direction, means for rotating the beam to let off yarn therefrom, said rotating means including a first driving disc assembly, a first driven disc assembly, a second driving assembly, the first driven and second driving assemblies being driven in unison by the first driving assembly, and being simultaneously adjustable, a second driven disc assembly driven by the second driving assembly and connected to the beam, the first driving and second driven assemblies being simultaneously adjustable, and means responsive to movements of the whip roll support resulting from variations in the tensions on the yarns for adjusting the simultaneously adjustable pairs of assemblies to vary the rate of rotation of the beam.

12. A let-01f for use in a loom having means for holding a warp beam and a lay for beating up inserted picks of filling, which comprises a whip roll engaged by the warp yarns being let oif the beam, a support for the whip roll, the support being movable and urged in one direction by the tension of the yarns acting on the whip roll, means urging the support in the opposite direction, means for rotating the beam to let off yarn therefrom, said rotating means including a pair of driving discs relatively movable axially, a pair of driven discs relatively movable axially, a belt connecting the pairs of discs, and means, including a single spring, acting to urge the discs of one pair closer together and to permit a limited separation of the discs of the other pair, and means responsive to movements of the whip roll support resulting from variations in the tension on the yarns for controlling the separation of the discs of the two pairs.

13. A let-off for use in a loom having means for holding a warp beam and a lay for beating up inserted picks of filling, which comprises a whip roll engaged by the warp yarns being let olf the beam, a support for the whip roll, the support being movable and urged in one direction by the tension of the yarns acting on the whip roll, means urging the support in the opposite direction, means for rotating the beam to let off yarn therefrom, said rotating means including a pair of driving discs relatively movable axially, a pair of driven discs relatively movable axially, a belt connecting the pairs of discs, and means, including a single torsion spring, acting to urge the driving discs closer together and to permit a limited separation of the driven discs, and means responsive to movements of the whip roll support resulting from variations in the tension on the yarns for controlling the separation of the discs of the two pairs.

14. A let-off for use in a loom, which comprises a loom shaft rotating throughout the operation of the loom, a warp beam supplying warp yarns, a whip roll engaging the warp yarns being lot 05 the beam, a support for the whip roll, the support being movable and urged in one direction by the tension of the yarns acting on the Whip roll, a let-off shaft connected to the beam and rotatable to rotate the beam to let off yarn therefrom, a variable speed device having an input shaft connectable to the loom shaft to be driven thereby and an output shaft connected to the let-off shaft, the device including a pair of driving discs and a pair of driven discs mounted on the input and output shafts, respectively, one disc of one pair and the opposite disc of the other pair being fast on their shafts and the remaining discs of the pairs being axially movable on the shafts but connected to the shafts for rotation therewith, a belt connecting the driving and driven discs, control means acting on the axially movable discs and operable to reduce the distance between the discs of one pair while permitting limited separation of the discs of the other pair, the control means including members acting on the axially movable discs and a connection between the members causing them to move in unison, means connected to the whip roll support and actuated by movements thereof to control the operation of the control means, and yielding means acting on the whip roll support and urging it to cause the whip roll to press against the yarns.

15. The let-off of claim 14, in which the yielding means acts on the whip roll support through the means actuated by movements of the whip roll support to control the operation of the controlling means.

References Cited in the file of this patent UNITED STATES PATENTS 1,307,241 Clark June 17, 1919 1,698,913 Hughes Jan. 15, 1929 2,271,202 Moessinger Ian. 27, 1942 2,350,954 Brown June 6, 1944 

